Moss, Algae or something

Which one do I call it? Algae, Moss or even particularly something that is growing on a tree stump. Tell me if you know?

Swallows (Naas Lane, Lydney)

The male tells the female, "there is no time to lose", but she says, "I can wait for a little time, about three weeks". "A couple of weeks, but I'll be all flapped out", says the male.

Great Spotted Woodpecker (Cyril Hart Arboretum)

I was very busy, so I didn't have much time. I took this one, a female GS Woodpecker.

Orange-tip butterfly (female)

The underside of the Orange-tip is very nice, but it is with the female, which more than the male can give. They are typically, a bit of an orange tip, and its beautiful.

King of the castle. Mandarin Duck (Cannop Ponds)

I love this Duck, it is standing and waiting for his female, purposely looking for anything bad to do her harm. What a good boy!